

Upgrade with a CURT 5th Wheel Pin Box
Looking for an upgrade? Look no further than a CURT 5th wheel pin box! Not all 5th wheel pin boxes are created equally. In fact, with so much weight hanging in the balance, the right choice can make all the difference in the world in terms of ride comfort and control.
CURT offers a variety of pin box options – from standard replacements to advanced shock-absorbing models – to provide you with the perfect solution to suit your needs, preferences and budget.
Ready to upgrade?
CURT Air Ride™ Pin Box Review by The Campoholics
CURT 5th Wheel Pin Box Comparison


Rota-Flex™
- Pivoting head with integrated rubber compound to absorb shocks
- Easy installation with no assembly required
- 18K - 21K weight capacity options


Air Ride™
- Internal airbag and built-in strut for enhanced shock absorption
- Easy installation with no assembly required
- 18K - 21K weight capacity options
Shock-Absorbing Technology for Improved Comfort & Control


Pivoting Head with Rubber Isolator
CURT Rota-Flex and Flex Air 5th wheel pin boxes are built with a pivoting head that allows the kingpin to articulate with the movement of the truck and trailer. An integrated rubber compound cushions this movement, absorbing shock and vibrations, resulting in a smoother ride for greater passenger comfort and improved driver control.
Built-in Air Bag & Strut
CURT Air Ride and Flex Air pin boxes are equipped with a built-in airbag and gas strut that provide enhanced shock absorption. Each CURT pin box has a pivot point that allows the kingpin head piece to articulate in a scissor-like motion. As the truck and trailer pass over rough, uneven roads, the airbag and strut absorb jerking, jarring and vibrations at the coupling point.




Standard Replacement Fifth Wheel Pin Boxes
If you’re looking for a basic fifth wheel pin box replacement, we also offer a variety of standard options with no shock-absorption upgrade. These standard kingpin boxes connect to virtually any 5th wheel trailer hitch and are designed to bolt into place using existing hardware on the trailer. They are available in capacities up to 21,000 pounds.
How to Choose the Right 5th Wheel Pin Box
Replacing or upgrading your pin box is very easy to do, particularly when your existing pin box is a CURT or Lippert model. Follow the steps below and use the diagrams and table to choose the right size 5th wheel trailer pin box for your RV.
- Look for the white sticker with a four-digit number on it. Example: 1621 or 1716
- What is the gross vehicle weight rating (GVWR) of the RV?
- Visually compare the illustration to the mounting wing on the trailer.
- Measure the length of the existing pin box from the front row of bolts to center of the kingpin.
- Measure all three bolt-pattern dimensions on existing pin box.
- Measure existing pin box width.
Pin Box Measurement Diagrams






OEM # |
Industry # |
Bolt Pattern |
Bolt Head Size |
Style |
A |
B |
C |
D |
E |
F |
G |
A – Bolt pattern horizontal distance |
|||||||||||
1621 |
L05 |
2-row |
15/16" |
Long |
7-7/8" |
2" |
-- |
5/8" |
17-3/4" |
25-5/8" |
12" |
0719 |
M15 |
2-row |
15/16" |
Medium |
7-7/8" |
2" |
-- |
5/8" |
9" |
16-7/8" |
12" |
1716 |
L07 |
3-row |
15/16" |
Long |
8-3/4" |
2-1/2" |
4-3/8" |
5/8" |
20-3/8" |
29-1/8" |
12-1/2" |
1116 |
M19 |
3-row |
15/16" |
Medium |
8-3/4" |
2-1/2" |
4-3/8" |
5/8" |
14-5/8" |
23-1/4" |
12-1/2" |